What is purpose of reactive power (VAR)?  

1 Answer

Answer :

It is an energy required to built up magnetic field to drive the power.  

Related questions

Description : What is purpose of Slip stabilization?  

Last Answer : It avoids oscillation of the AC machine (Rotor oscillations).  

Description : What is purpose of Stator current limiter?  

Last Answer : It limits the stator current.

Description : What is purpose of Rotor current limiter?

Last Answer : It limits overloading of rotor.  

Description : What is purpose of Rotor angle limiter?

Last Answer : It limits generator voltage & rotor voltage.  

Description : What is purpose of Load angle limiter?  

Last Answer : Load angle limiter, it either limits the angle between grid load center and the rotor axis or generator terminal & rotor axis. 

Description : What is purpose of connecting thyristor bridges in parallel?

Last Answer : Thyristor bridges are connected in parallel to improve current rating.  

Description : What is the purpose of RC network across thyristor?

Last Answer : RC network across each thyristor protects against Hole Storage Effect.  

Description : What is material used in making non-linear resistor & purpose of it in field discharge resistor?  

Last Answer : Silicon carbide materials used for making non-linear resistor. The purpose of this resistor is to avoid surge voltage when field breaker opens. These resistors are connected in parallel to the main field winding (Rotor). 

Description : The unit of apparent power in a purely inductive circuit is called the _____________. A. kva B. var C. emf D. watt

Last Answer : Answer: B

Description : When the Zero sequence reactance arises? 

Last Answer : If a machine is operating with an earthed neutral, a system earth fault will give rise to zero sequence current in the machine. 

Description : When the negative sequence reactance arises?

Last Answer : Negative sequence arises whenever there is any unbalance present in the system. Their effect is to set up a field rotating in opposite direction to the main field.

Description : What is the advantage of field forcing in the rotor?  

Last Answer : Field forcing acts for 10 seconds to maintain the generator terminal voltage during fault condition so as to operated the protection relays. 

Description : What is the advantage of Static Excitation?  

Last Answer : Fast response time, high reliability, interchangeability of parts during operation, less wear & tear due to static devices & less maintenance.  

Description : Why reactors are provided in Thyristor bridges? 

Last Answer : Reactors are provided to limit the rate of rise of current (di/dt) in the device, thereby avoiding possible damage to the device. They also effect a proper sharing of load among thyristor bridges when connected in parallel. 

Description : What is Inverter operation? 

Last Answer : When firing angle a = 90º the positive & negative voltages areas are equal. With a higher than 90º the negative areas are greater so the total voltage becomes negative. This condition is termed as 'Inverter Operation".  

Description : What is firing angle? 

Last Answer : The angle in the AC cycle at which the thyristor starts conducting at the application of positive voltage to gate is known as the firing angle (α)

Description : How over voltage is produced in Field breaker?

Last Answer : Over voltages appear if synchronous generators and motors fall out of step inducing an AC voltage in the field system. Depending on the type of construction of the machine and the slip this ... -permissibly high, for this purpose over voltage protectors are provided in the field breaker cubicle.  

Description : What is material used in making semiconductor?

Last Answer : Silicon & Germanium are the raw materials used for making semiconductor. Semiconductors are located between conductors & insulators in the resistivity spectrum & allow current to flow only under certain conditions. 

Description : What is Thyristor?

Last Answer : Thyristor is a four or more layer semiconductor device & having 3 or more junctions. It is also called Silicon Controlled Rectifiers (SCR). A healthy SCR must block in both the directions at least 1MΩ resistance, a fused SCR will conducts in both directions. 

Description : What is Diode?

Last Answer : Diode is a two-layer semiconductor device, conducts only positive cycles when applied to anode

Description : What is "dirty power" and is my space heater generating it?

Last Answer : Harmonics, they are the source of this dirty power you speak of. DC switching power supplies are some of the worst offenders. These are transients and non 60hz frequencies that are generated by said appliance. ... your heater works but I'm guessing it uses some sort of switching to run on low power.

Description : How do I calculate how long a battery will power an LED?

Last Answer : answer:AA Alkaline batteries have between 1800 and 2500 mAh and C Alkaline batteries up to 8000 mAh. mAh/mA = hours Calculation is batteries mAh divided by load 200 mA, for AA 9 to 12 hours and 40 hours for C.

Description : Are you still using power when things are connected to the outlet but aren't on?

Last Answer : There is power consumption to keep them in “instant on”. Long time ago a TV used to take time to warmup, same with a lot of other equipment. Now they are constantly sucking a small bit of power.

Description : If you’re charging a cellular phone using a home outlet, wouldn’t the more powerful current charge a phone faster than using a vehicle’s power to charge the same cellular phone?

Last Answer : Do you understand the difference between AC and DC?

Description : What is the best "engine" for a power tool drag racer?

Last Answer : Fred931 How about this it has ⅓ horse and 22,000 RPM.

Description : Can I hack and extend my Macbook's power cord?

Last Answer : Yes, if you're prepared to do it right using a soldering iron and heat-shrink tubing. If you have no experience with this kind of thing you might think twice. For starters, find out how many ... work. Making a super-long cable, however, might create too much resistance or capacitance in the line.

Description : How can I keep my power cords, charging docks, and various other electronics related cords from taking over all of my extra storage space?

Last Answer : I use twisty ties because I’m ghetto. But it looks like the Container Store has a bunch of options. I’d imagine most office supplies stores would have stuff too.

Description : Is it unsafe to plug a power strip into an extension cord permanently?

Last Answer : Its unsafe. If you need power permanently you need to run to run a new box and receptacle off a pre-existing circuit. You might need to run a whole new circuit and add a new breaker in your electrical panel if what your using requires more juice than a pre-existing circuit can safely handle.

Last Answer : that At the rate Electron Flowing Become Work Done Is Or That At the rate Electricity Power Other In strength Transformed Is Him Electric Power Says.

Last Answer : any Person Or Of the object Single In time Made Of work The amount Power Says.

Description : State the applications of power electronics.

Last Answer : Power electronics applications are extended to various fields such as: 1. Aerospace, 2. Automotive electrical and electronic systems, 3. commercial, 4. industrial, 5. residential, 6. telecommunication, 7. transportation, 8. utility systems,

Description : What is drive circuit in power electronics?

Last Answer : Driver is used for Motion Control through the use of power electronics.

Description : Is lavender (lavandula angustifolia var. rosea) hardy in zone 6b?

Last Answer : answer:Yes. Here where there are pockets of zone 5 (sheltered and sunny) it winters over.. On my windy hill that gets the brunt of the gales from the NW and is considered zone 4b, it does ... before the first heavy frost. You can have a bed entirely of the different species of lavender. Lucky you.

Description : Certain strains of Streptococcus lactis var. maltigenes may produce A.bitter flavor B.acid flavor C.burnt or caramel flavor D.none of these

Last Answer : C.burnt or caramel flavor

Description : Certain strains of Streptococcus lactis var. maltigenes may produce A.bitter flavor B.acid flavor C.burnt or caramel flavor D.none of these

Last Answer : C.burnt or caramel flavor

Description : . Mimicry weed in rice field is a). Wild rice (Oryza sativa var fatua) b). Echinochloa colona c). Echinochloa crusgalli d). All of these

Last Answer : d). All of these

Description : Series capacitors on transmission lines are of little use when the load VAR requirement is (a) large (b) small (b) fluctuating (d) any of the above

Last Answer : (b) small

Description : A static VAR compensator is a (A) series connected thyristor based controller (B) shunt connected thyristor based controller (C) energy storage device (D) combined series–shunt connected controller 

Last Answer : Shunt connected thyristor based controller

Last Answer : Series capacitors on transmission lines are of little use when the load VAR requirement is small.

Description : What is static var compensator ?

Last Answer : Static VAR Compensator (SVC)  SVC are use for regulating transmission voltage and for improving power quality of industrial load. SVC is made from one or more banks ... system. Static VAR Compensator is more reliable than dynamic compensation scheme like synchronous condenser.

Description : What is the so-called "notch" on an iPhone?

Last Answer : It is a small cutout in the screen, where the front facing camera is located. It is hated, because it reduces usable screen space at the top. Imagine a webcam on top of your monitor, but instead of being actually on top, it hangs down into the screen, obscuring part of it.

Description : A camcorder battery plate claims that the unit stores 2700mAHr at 7.2v.What is the total charge and energy stored?

Last Answer : Homework?

Description : Can anyone recommend a portable radio?

Last Answer : C Crane, Sangean and Eton are all quality brands. For almost 20 years I have been using something extremely similar to this: CC Skywave AM, FM, Shortwave, Weather + Alert and VHF ... /FM/Shortwave Radio $24.99 Here are some NY Times Wirecutter recommendations: The Best Emergency Weather Radio

Description : Can one turn a profit by scavenging materials from landfills?

Last Answer : Most have laws against doing any scavenging. Had a friend that lost his jobs in early 1990's (he was VP of insurance company that collapsed) he made a living driving around affluent neighbors picking-up ... wooden box that was crushed but still locked - - surprise 3 gold rings one was worth $2000 !

Description : Any ideas on how to get a spider out of the CD player in my car?

Last Answer : Might want to use a hair dryer for a short time to encourage it to leave. Then, use a cd cleaning disc to remove the webbing and polish the lens.

Description : What is happening when the engine cuts off on a newer vehicle?

Last Answer : The engine does indeed stop and your accessories are powered by the battery. When you step on the throttle the battery sends high current to the starter which is strong enough to spin the engine up to speed. ... nice write-up in the GM system. They were one of the first to try it. Stop Start System

Description : Is there a Headset/Gaming Headset that works for most platforms?

Last Answer : Turtle Beach makes a lot of sets that work across platforms. Their stuff is pretty quality too.

Description : Do truck manufacturers use standardized wiring harnesses regardless of the model?

Last Answer : A lot do nut it of course, depends. It’s much easier to use the same harness for each vehicle in the product line. It also makes upgrades easier. This type of thing came up frequently when I was a teenager working in a car audio installation shop.

Description : Why is owning or using a cell phone jammer illegal?

Last Answer : answer:Because it disrupts people’s ability to use a communication device. That carries a whole host of potential problems. The only reason to use one is to be a dick.

Description : Is the electronic product affected by a leaky (on the side) battery that has been taped over?

Last Answer : answer:If I discovered a leaking battery anywhere, it would go straight into the trash. Batteries cost so little why take unnecessary chances with one that leaks. Makes no sense to me at all.